WARF TECHNOLOGIES

N-type bismuth vanadate (BiVO₄) has emerged as a promising photoanode for use in solar water-splitting cells given its favorable light absorption and conduction band characteristics. To date, however, efficiency levels hover far below what is expected because the material suffers from poor electron transport properties. Methods to address this problem by synthesizing porous BiVO₄ have until now yielded large particles that hinder performance.

UW–Madison researchers have developed a method for synthesizing nanoporous BiVO₄ electrodes with large surface areas. The material is made up of a porous network of BiVO₄ particles smaller than 150 nm and coated with oxygen evolution catalyst. The small size of the particles addresses prior drawbacks by increasing a property called electron–hole separation yield. The material is made by applying a vanadium solution to a type of bismuth crystal. The mixture is heated and converted into a porous network of BiVO₄ particles.

• Electrodes for use in solar cells that directly utilize solar energy to drive chemical reactions such as water splitting, CO₂ reduction and biomass conversion.

• Improves solar-to-chemical conversion efficiency
• Can be efficiently paired with any photocathode owing to its earlier photocurrent onset and a high fill factor
• Promising results using inexpensive materials and simple production methods
• Small particle size
• Large surface area

The new electrodes have demonstrated superior electron-hole separation yields (.90 at 1.23 V versus RHE).

For More Information About the Inventors

• Kyoung-Shin Choi

Publications

• Kim T.W. and Choi K-S. 2014. Nanoporous BiVO₄ Photoanodes with Dual-Layer Oxygen Evolution Catalysts for Solar Water Splitting. Science. 343, 990-994.

Tech Fields

• Clean Technology : Biobased & renewable chemicals & fuels
• Clean Technology : Solar, wind & water technologies